10. Addition Reactions

For the alkynes shows here, show the product(s) expected to form when treated under the following conditions: (vi) H₂SO₄, HgSO₄, H₂O. If you expect two products, show both.

(c)

Predict the product(s) that would result when the following molecules are allowed to react under the following conditions: (ii) 1. Hg(OAc)₂ 2. NaBH₄.If there is no reaction, write 'no reaction.'

(a)

Predict the product of the following aldehyde/ketone syntheses.

(d)

Would you expect the following to produce an equal or unequal mixture of stereoisomers?

(c)

Predict the product of each of the following alcohol synthesis reactions.

(a)

In 1973, Caine and Tuller reported a synthesis of racemic oplapanone, a sesquiterpene isolated from Oplopanax japonicus (a deciduous shrub) involving a reaction we learned in this chapter. Predict the product of the reaction shown. (Caine, D.; Tuller, F. N. J. Org. Chem. 1973, 38, 3663.)

Assessment 8.74 revealed that oxymercuration could be used to make cyclic esters. Suggest a likely mechanism for this transformation.

Oxymercuration–reduction, like acid-catalyzed hydration, can be modified to synthesize ethers. Suggest an alkene and the appropriate reaction conditions to synthesize the following ethers.

(b)

The formation of five-membered ring ethers is an important goal in synthetic organic chemistry because tetrahydrofurans are contained within a number of antitumor natural products. Toward that end, a one-pot synthesis of a bis-THF containing compound was developed (Eur. J. Org. Chem. 2010, 6263–6268). Suggest a mechanism for this transformation.

Show how you would synthesize each compound using methylenecyclohexane as your starting material.

(a)

Show how you would accomplish the following synthetic conversions.

c. 3-methylpent-1-ene → 3-methylpentan-2-ol

Explain why acid-catalyzed hydration would be a poor choice for the reaction in (c).

Predict the major products of the following reactions.

c. 4−chlorocycloheptene + Hg(OAc)₂ in CH₃OH

d. the product from part (c), treated with NaBH₄

Show how you would accomplish the following synthetic conversions.

a. but-1-ene → 2-methoxybutane

b. 1-iodo-2-methylcyclopentane → 1-methylcyclopentanol

In light of your answer to Assessment 8.73, predict the product of the following oxymercuration–reduction reactions, each of which results in a single product. [Don't worry about the absolute stereochemistry, though these reactions are also stereoselective.]

(b) This reaction sequence was used in the synthesis of (+) -lineatin, a monoterpene aggregation pheromone from the female ambrosia beetle Trypodendron lineatum (Org. Lett. 2004, 6, 1449–1452).

In light of your answer to Assessment 8.73, predict the product of the following oxymercuration–reduction reactions, each of which results in a single product. [Don't worry about the absolute stereochemistry, though these reactions are also stereoselective.]

(c) Oxymercuration–reduction was used in the stereoselective synthesis of the macrolactone core of neopeltolide, a marine macrolide isolated from a Caribbean sponge that has potent anticancer activity (Org. Lett. 2012, 14, 2346–2349).